A Passive Transponder for Visible Light Identification Using a Solar Cell

We introduce a passive transponder for visible light identification using a solar cell. The solar cell in the transponder receives reader light and generates current for the transponder to respond. The ac component of the solar cell current is used for detecting the interrogating signal from the reader and the dc component is used for supplying electric power to the devices in the transponder. In experiments, with the interrogating light from a 3 × 3 visible LED array in the reader, the maximum read distance of the transponder with an 11 cm × 16.5 cm silicon solar cell was ~1 m.